Cumene hydroperoxide (hereinafter may abbreviate “CHP”) is a precursor of phenol production process using cumene process and is produced by liquid phase oxidation of cumene.
Two CHP production processes by liquid phase oxidation of cumene have been known. One is carried out without catalyst (refer to patent document 1), the other is carried out with catalyst (refer to patent document 2). Both processes use an oxygen-containing gas as oxidizing agent fed into a reactor. Usually, air (oxygen content is around 21%) is used as the oxygen-containing gas from the industrial standpoint of safety because high oxygen content of oxygen-containing gas leads to the possibility of explosion and standpoint of cost performance. Under the present situation, even though pure oxygen is used, oxygen is diluted to an oxygen-containing gas having low oxygen content (equal to or lower than the oxygen content of air) and fed into the reactor.    Patent document 1: Japanese Patent No. 3107409    Patent document 2: Japanese Patent No. 3061394